Astronomer helping with big project to study universe’s expansion
Kansas University astronomy professor Gregory Rudnick looks back in time — literally.
Using a telescope, he can see millions of years into the past, studying how our universe has evolved in the more than 13 billion years since the Big Bang.
“It’s like a time machine,” Rudnick said. “The further we look into the galaxy, the further back in time we are looking.”
And he and fellow scientists are planning to look deeper into space than ever before. Rudnick is taking part in a joint Department of Energy-National Science Foundation project to create a 3D map of the universe. Researchers are, at a cost of $100 million, equipping the telescope at the Kitt Peak National Observatory in southeast Arizona with a state-of-the-art spectrograph that will allow them to see more than halfway across space, a distance of 8 billion light years.
As part of BigBOSS (Baryon Oscillation Spectroscopic Survey), scientists will, between 2018 and 2023, survey more than 20 million galaxies. KU is collaborating on the project with more than 30 universities and astronomy organizations from six different countries.
“We’re lucky at the University of Kansas that we’re able to get in on the ground floor,” said Rudnick. “This will create an unparalleled quality of data for what I want to study. It will give us the best view we have of how galaxies have grown over the last 8 to 9 billion years.”
Rudnick has long been fascinated with galaxies and, using the information gleamed from BigBOSS, plans to find out more about how they have evolved. He will attempt to answer questions like, why is the Milky Way the way it is? What are the origins of galaxies? Why do they look different from one another? “Some galaxies are in clusters, like an urban environment,” Rudnick explained. “Other galaxies are more isolated, rural, like the boonies.”
In the late 1990s, scientists discovered that the universe — and thus space-time — was expanding at a rate faster than any of them had ever before thought. A mysterious force was found to be causing that acceleration: dark energy, which exerts negative pressure, counteracting gravity and pulling galaxies apart. While no one has ever seen it, dark energy is said to make up roughly 70 percent of the universe (about a quarter is thought to be dark matter, which holds galaxies together, with normal matter making up the remaining 5 percent).
The BigBOSS study will be able to tell researchers how far apart galaxies were at different periods in time. Rudnick says the map will be more informative — “by a factor of 10” — than anything space scientists have ever had at their disposal. The project will attempt to surmise how exactly dark energy has influenced the universe’s expansion over the last two-thirds of its existence. “It’s one of the biggest unsolved problems in physics,” Rudnick said.
As technology improves, humans will be able to see even further into the universe — this project will look at just 20 million galaxies; there are potentially trillions — and, thus, even further back into time, learning more and more about where we came from in the process. Much of what is known about our universe was discovered in the past 10 to 15 years, Rudnick noted.
Who knows what else scientists will discover as a result of BigBOSS? It could even tell us whether or not we’re alone in the universe. For his part, Rudnick says discovering extraterrestrial life is “a question of when, not if.” Stay tuned.